I'm trying to learn DirectX programming. Looking at different tutorials there is something about vertices that I find a bit confusing.
I know that DirectX uses vertices with four elements (x, y, z, w). I saw many tutorials (example http://msdn.microsoft.com/en-us/library/ff729721(v=VS.85).aspx) passing XMFLOAT3 as vertices positions omitting the w component.
How does this works? Assuming that passing XMFLOAT3 or XMFLOAT4 doesn't change DirectX behavior (true?) should I set the w to 1 in the vertex shader or does DirectX assume it to be 1 by default?